From: Douglas Livingstone <rampant@...>
Date: 2005-06-13T11:49:14+09:00
Subject: Re: Only if the object exists

On 6/12/05, Mark Hubbart <discordantus@gmail.com> wrote:
> IMHO, it wouldn't be a "heavy language modification" (irrespective of
> the work required). I've always felt uncomfortable with the fact that
> an assignment in a statement modifier doesn't show up for the
> statement it is modifying, even though it is executed first. I feel
> the following two examples should be equivalent:
> 
>   if t = foo
>     t.bar
>   end
> 
> -- and:
> 
>   t.bar if t = foo
> 

Hmm, using a Ruby 1.8.x:

irb(main):001:0> class Foo
irb(main):002:1>   def name
irb(main):003:2>     'foo'
irb(main):004:2>   end
irb(main):005:1> end
=> nil
irb(main):006:0> foo = Foo.new
=> #<Foo:0x2be07f0>
irb(main):007:0> bar.name if bar = foo
NameError: undefined local variable or method `bar' for main:Object
        from (irb):7
irb(main):008:0> bar = nil
=> nil
irb(main):009:0> bar.name if bar = foo
=> "foo"

Seems like the same "reading ahead of itself" problem of trying to do
the whiteout quiz on a file without perfect syntax. Example:

irb(main):012:0> 89u33@$T$#$b if false
SyntaxError: compile error
(irb):12: syntax error
89u33@$T$#$b if false
     ^
        from (irb):12

Should you get a syntax error on code never called?

Douglas